It means 'back and front', an indication the item is plated (either gold or silver).
A 525 stamp indicates that the metal in the stamped piece is 52.5 percent gold. This is the same thing as the marking 14K for 14 karat gold.
I have a 9ct gold ring (with pink sapphires) which has this marking on it, it is made by Angus & Coote jewellers. **375 stamp means 9ct gold - 37.5% pure gold, or 375 parts per 1000. This can be stamped on white gold or yellow gold. 585 is 14ct gold, 750 is 18ct, and 1000 is 24ct or PURE GOLD. Guessing AC16 is Angus & Cootes stamp.
14 carat gold
62.5 % gold
Gold electroplate. Not gold.
The stamp mark JF14K indicates that the gold necklace is made of 14-karat gold. It is a standard marking that jewelers use to indicate the gold purity of a piece of jewelry. 14-karat gold is made up of 58.3% gold and 41.7% alloy metals, making it a popular choice for jewelry because it is both durable and beautiful.
375 is the marking for 9 carat gold. Usually vintage European will have this marking.
The BX stamp on a ring is probably just a jeweler's signature marking. It does not indicate value or purity of the ring.
gold
This marking means that the piece is gold plated. The 12K refers to purity of the gold. The 00/15 means that the gold is 15 per cent of the total weight.
On a gold ring the stamp 585 is meant to indicate that it is 58.5%, or 14 karat gold. However, I urge anyone wishing to buy jewelry to be very careful when judging gold by the marking. If you are dealing with a reputable jewelry store or jeweler, you are probably safe.
The Stamp YAG Means Gold Coated Silver